Centralized traffic controlling system for railroads



Jan. 5, 1937. O D|CKE 2,067,151

CENTRALIZED TRAFFIC CONTROLLING SYSTEM FOR RAILROADS Filed Dec. 50, 19324 Sheets-Sheet l ATTORNEY 0. H. DICKE Jan. 5, 1937.

CENTRALIZED TRAFFIC CONTROLLING SYSTEM FOR RAILROADS Filed Dec. 30, 19324 Sheets-Sheet n on. G L mm T 1 v Q u a n flW Q 2 u u 3 3 3 u N? mm mmmmi mm ni mm. 03 G {u I 3'3 11 u u E w n u u w L :3 n u d fl 1 h E u E\t fii a m rs 8 2 Q n +|r grlmvjllg as J w v 3 N +71 w lt Jan. 5, 1937.o. H. DICKE 2,067,151

CENTRALIZED TRAFFIC CONTROLLING SYSTEM FOR RAILROADS Filed Dec. 30, 19324 She'cs-Sheet :s

T I E W ATTORNEY Jan. 5, 1937. o. H. DICKE Filed Dec. 30, 1932CENTRALIZED TRAFFIC CONTROLLING SYSTEM FOR RAILROADS 4 Sheets-Sheet 4Fla-.4.

TYPICAL OPERATION CHART N0.0F QELAY QEFERENCE CHARACTERS N0.0F

OPERAI'ION FP VP 1v 2v 5v 4v CHANNEL 1 nu. PU. 10H.

2 DA. PU. 26H.

5 PU. DA.

4 DA. PU. 56H.

5 rev. P.U.

e IDA. nu 46H.

7 nu. DA.

8 DA. nu. 56H.

a nu. PU.

10 DA. DA. 66H.

11 PU. DA.

12 DA. DA 76H.

15 PU. Ru.

14 DA. 12A. am.

15 nu. DA.

16 DA. DA-

ATTORNEY Patented J an. 5, 1937 UNITED STATES CENTRALIZED TRAFFICCONTROLLING SYSTEM FOR RAILROADS Oscar H. Dicke, Rochester, N. Y.,assignor to General Railway Signal Company, Rochester,

Application December 30, 1932, Serial No. 649,606

18 Claims.

This invention relates to centralized traffic controlling systems forrailroads, and more parti'cularly pertains to the communicationapparatus employed in such systems.

In a centralized traflic controlling system, employing a coded type ofcommunication system, such as disclosed, for example, in the pendingapplication of Judge and Bushnell, Ser. No. 640,- 062, filed October 28,1932, corresponding to British Patent 419,399, it is desirable to employstep-by-step mechanisms which will require a minimum amount of apparatusto accomplish the required operations.

The present invention proposes a step-by-step mechanism for coded typecommunication systems, which mechanism includes a plurality of steppingrelays for making up a plurality of local channel circuits. This bank ofstepping relays is so organized, that each relay adds two channelcircuits to the total capacity of the bank,

The arrangement of the stepping relay bank, in order that each steppingrelay may be capable of providing two channel circuits, is such that thesteppingrelays are picked up sequentially until all of the relays arepicked up, and

then the relays are deenergized sequentially in the same order that theyare picked up. Thus, two stepping relays provide four channel circuits;three stepping relays provide six channel circuits, four stepping relaysprovide eight channel circuits; and so on, the number of channels beingincreased by two by the addition of each stepping relay.

Other objects, purposes and characteristic features of the presentinvention will be in part obvious from the accompanying drawings and inpart pointed out as the description thereof progresses.

In describing the invention in detail, reference will be made to theaccompanying drawings in which like reference characters designatecorresponding parts throughout the several views, and in which:

Fig. 1 illustrates a stepping relay bank arranged in accordance with thepresent invention;

Fig. 2 illustrates a stepping relay bank arranged in accordance with thepresent invention and similar to the bank illustrated in Fig. 1 exceptwith modified means for providing the sequential deenergization of thestepping relays;

Fig. 3 illustrates a stepping relay bank arranged in accordance with thepresent invention and similar to the stepping bank illustrated in Fig. 2but with modified stick circuits for providing the sequentialdeenerglzation of the stepping relays; and

Fig. 4 is a typical operation chart showing the sequence of relayoperation during a complete cycle. The abbreviation P. U. refers to thepicking up of the associated relay and the abbreviation D. A. refers tothe dropping away of the associated relay.

For the purpose of simplifying the illustration and facilitating in itsexplanation, the various parts and circuits constituting the embodimentof the invention have been shown diagrammatically and certainconventional illustrations have been employed, the drawings having beenmade more with the purpose of making it easy to understand theprinciples and mode of operation than with the idea of illustrating thespecific construction and arangement of parts that would be employed inpractice. Thus, the various relays and their contacts are illustrated ina conventional manner and symbols are used to indicate connections tothe terminals of batteries, or other sources of electric current,instead of showing all of the wiring connections to these terminals.

The symbols and are employed to indicate the positive and negativeterminals respectively of suitable batteries, or other sources of directcurrent; and the circuits with which these symbols are used, always havecurrent flowing in the same direction. The symbols (B+) and (13-)indicate connections to the opposite terminals of a suitable battery, orother direct current source which has a central or intermediate t'apdesignated (CN); and the circuits with which these symbols are used, mayhave current flowing in one direction or the other depending upon theparticular terminal used in combination with the intermediate tap (CN).

While certain features of the invention are applicable to and useablewith any type of com munication system for centralized traffic control,the specific embodiment of the invention has been shown in a formadapted for use with a selective communication system of the duplexcoded type, shown and described in detail in the above mentioned pendingapplication of Judge and Bushnell, Ser. No. 640,062, filed October 28,1932. Thus, before considering the structure and mode of operation ofthe parts constituting this invention, it becomes desirable to explainsome of the features of this communication system insofar as material toan understanding of the present invention, reference being made to saidprior application for other details of the structure and operation ofsuch a communication system not directly related to the features of thisinvention.

The centralized trafiic control system contemplated as embodying thepresent invention includes a central control ofiice and a plurality ofoutlying field stations to which and from which controls and indicationsrespectively are transmitted. The control ofilce and each of the fieldstations includes a bank of stepping relays which are operated insynchronism through cycles of operation comprising a predeterminednumber of steps. On each of these steps, the control line circuitconnecting the control office with the several field stations, isconditioned in accordance with code calls and controls for the selectionof a particular station and the transmission of controls to thatstation. Similarly, on each of these steps, a field station may beconditioning an indication line circuit interconnecting the controlofllce with the several field stations, whereby that field station isregistered in the control ofilce followed by thestoring of itsindications.

The conditioning of the line circuits at the control ofiice and thefield stations, as well as the reception of these conditions at therespective 10- cations, is accomplished on each step by the provision ofwhat are conveniently termed local channel circuits.

Although these local channel circuits are employed both for thetransmission and reception of controls and for the transmimion andreception of indications at the several locations as required inaccordance with a communication system of this character, the presentinvention has been shown as applied to the step-by-step apparatus at afield station for the reception of controls at that station.

Description of apparatus With reference to Fig. 1 of the accompanyingdrawings, the step-by-step mechanism at a typical field station of acentralized traiflc controlling system is illustrated as having athree-position biased-to-neutral line relay F included in a line circuitI. The line relay F is provided with polar contacts 2 and 3 which areoperated to right hand positions by a positive impulse on the linecircuit l and which are operated to left hand positions by a negativeimpulse on the line circuit I.

A quick acting line repeating relay FP is associated with the line relayF to repeat each energization of the line relay irrespective of thepolarity of such energization. This is accomplished as the polar contact2 of the line relay F closes the energizing circuit for the relay FPwhen in either polar position, as will be apparent from the drawings.

A slow acting relay SA is energized each time the quick acting linerepeating relay FF is picked up by reason of the closure of its frontcontact 4 included in circuits obvious from the drawings. This slowacting relay SA is provided with such slow acting characteristics thatit is slow in picking up and slow in dropping away, although it is to beunderstood that the drop-away period is much slower than the pick-upperiod.

The stepping relay bank is of the type having a plurality of full steprelays V with a single half step or steering relay VP common to each ofthe full step relays. For example, the stepping relay bank illustratedincludes the full step relays IV,

2V, 3V, and 4V together with the hall step relay VP.

Associated with the stepping relay bank are two polarized relays SR. andDR which are of the two-position polarized magnetic stick type tooillustrate one manner in which the channel circuits may be utilized.However, it is to be understood that the channel circuits closed by thestepping bank may be employed for any purpose desired in a communicationsystem contemplated in accordance with the present invention. The relaySR has a polar contact 5 which is operable to either right or left handpositions dependent upon the positive or negative energize.- tion of itswindings; while the relay DR has a contact 6 which is operable to eitherright or left hand positions dependent upon whether it is energizedpositively or negatively.

It is believed that the nature of the invention, its advantages andcharacteristic features can be best understood from the standpoint ofoperation of the system.

Operation With the system in a normal condition of rest,

each of the relays illustrated in Fig. 1 is in its normal deenergizedcondition and all of their contacts are dropped away.

In describing the stepping relay bank illustrated in Fig. 1 and themodifications illustrated in Figs. 2 and 3, it is convenient to dividethe operating characteristics into three divisions, namely, adescription of the operation of the half step relay, a description ofthe pick-up and stick circuits of the full step relays, and adescription of the channel circuits closed by the full step relays. Thisarrangement is more particularly desirable inasmuch as the modificationsillustrated in Figs. 2 and 3 refer more particularly to the pick-up andstick circuits of the full step relays while the half step or steeringrelay and the channel circuits are in each case identical with Fig. 1.

In considering the operation of the stepping relay bank, it isconvenient to assume that the line relay F is included in a line circuitI having a plurality of different series of impulses applied theretowith the polarity of the impulses of each series so selected as toprovide code comblnations and controls for the field stations of acentralized trafiic controlling system as disclosed, for example, in theabove mentioned application of Judge et al., (Ser. No. 640,062, filedOctober 28, 1932.

Although each series of impulses applied to the line circuit I has thepolarity of its impulses arranged in accordance with some code plan,such coded arrangement is immaterial for an understanding of the presentinvention, except that it shouldbe understood, that each such impulse isof either positive or negative character selectively chosen so as tooperate a particular device in accordance therewith, as shown, althoughother kinds of distinctiveness of currents may be employed if desired.Also, the first impulse of each series of impulses is relatively long ascompared to the remaining impulses so as to provide sufilcient time forthe slow acting relay SA to be picked up at the beginning of each seriesand the time space between successive impulses of the series issufliciently short to provide that the relay SA does not drop awayduring such time spaces. Also, between each different series of impulsesis a prolonged time space which is longer than the time spaces betweenthe successive impulses in a 7 iii series, so that the relay SA may havesufllcient time in which to drop away. In other words, the relay SA ispicked up at the beginning of each series and is dropped away at the endof each series.

Operation of half step or steering relay-The application of the firstimpulse of a particular series to the line circuit I is repeatedsuccessively by the relays F, FP, and SA irrespective of the polarity ofthat impulse, as previously explained.

As the first impulse is relatively long and maintains the energizationof the relay FP subsequent to the picking up of the contacts of therelay SA, the first pick-up circuit for the relay VP is closed from (3+)through a circuit including back contacts I, 8, 9, and III of thestepping relays IV, 2V, 3V, and V respectively, upper winding of therelay VP, front contact I5 of the relay SA, front contact I5 of therelay FP, to (ON).

This energization of the relay VP causes its contacts to pick up,thereby closing a stick circuit from through a circuit including frontcontact ll of relay SA, front contact I8 of relay VP, lower winding ofrelay VP, to This stick circuit for the relay VP closed during the firstenergized period of the line circuit maintains the relay VP energizedthroughout the succeeding time space or deenergized period of the linecircuit.

When the line circuit is deenergized for the first deenergized period,such condition is repeated by the relays F and PP, but the relay SA"remains picked up throughout the period. The drop-away of the contactsof the relay FP causes the first stepping relay IV to be picked up andtobe .stuck up, the details of which will bepointed out hereinafter.

Assuming that the relay IV is picked up and stuck up, then upon theapplication of the second impulse to the line circuit and the responseof the contacts of the relay FP, a differential stick circuit for therelay VP is closed from (B) through a circuit including front contact I9of relay VP, front contact I of relay IV, back contacts 8, 9, and III ofstepping relays 2V, 3V and 4V respectively, upper winding of relay VP,front contact I5 of relay SA, front contact I6 of relay F'P, to (CN) vIt is apparent that current in this circuit flows from left to right inthe upper winding of relay VP, while the current in the lower winding ofrelay VP flows from right to left. As the windings of the relay VP areconstructed to have a substantially equal number of ampere turns, themagnetic fluxes produced by these windings buck each other so that theresulting flux is substantially zero, thereby allowing the contacts ofthe relay VP to drop away.

It is, of course, to be understood that the relay VP may be so designedthat the bucking magnetic flux provided in the upper winding is slightlygreater than the magnetic flux provided in the lower winding to therebycompensate for any residual which may be in the core structure of therelay. However, it is sufiicient for an understanding of the presentinvention to know that the resultant magnetic flux is reduced to zero,or at least to such a value sufficiently low to allow its contacts todrop away.

The simultaneous opening of front contacts I8 and I9 deenergizes both ofthe windings of the relay VP. This de-energized condition of the relayVP continues throughout the following time space or de-energized periodof the line circuit I.

The second de-energized period or time space on the line circuit isrepeated oy the relay FP causing the stepping relay 2V to be picked upand stuck up, as will be later explained in detail.

Thus, the application of the third impulse to the line circuit and theresulting response of the relay FP causes the relay VP to be againpicked up by reason of a circuit closed from (13+), through a circuitincluding. front contact 8 of relay 2V, back contacts 9 and II) ofrelays 3V and 4V respectively, upper winding of the relay VP, 1

front contact I5 of relay SA, front contact I6 of relay FP, to (CN).This energization of the relay VP causes its contacts to be picked up,thereby closing its stick circuit including its front contact I8, sothat the relay VP remains stuck up throughout the succeedingde-energized period marked off by the absence of current in the linecircuit.

The third de-energized period or time space on the line circuit isrepeated by the relay FP causing the stepping relay 3V to be picked upand stuck up, as will be later explained in detail.

Thus, the application of the fourth impulse to the line circuit and theresulting response of the relay Fl? causes the relay VP to again dropaway by reason of the closure of its bucking stick circuit. This buckingstick circuit is closed from (18-), through a circuit including frontcontact I9 of relay VP, front contact 9 of relay 3V, back contact III ofrelay 4V, upper winding of relay VP, front contact I5 of relay SA, frontcontact I5 of relay FP, to (CN). The direction of current which flows inthis circuit is opposite to that which flows in the stick circuitincluding the lower winding of the relay VP, so that the magnetic fluxin the relay VP is reduced to substantially zero, as previouslyexplained, causing the contacts of this relay to drop away. Thisde-energized condition of the relay VP maintains throughout the nexttime space marked off on the line circuit.

The fourth de-energized period or time space on the line circuit isrepeated by the relay FP causing the stepping relay 4V to be picked upand stuck up, as will be later explained in detail.

Thus, the application of the fifth impulse to the line circuit I and theresulting response of the relay FP causes the relay VP to beagain pickedup by reason of a circuit closed from (B+), through a circuit includingfront contacts II, I2, I3, and I4 of stepping relays IV, 2V, 3V, and 4Vrespectively, front contact II) of relay 4V, upper winding of relay VP,front contact I5 of relay SA, front contact I6 of relay FP, to

(CN). This energization of the relay VP causes its contacts to be pickedup, thereby closing its stick circuit including front contact I8, sothat the relay VP remains picked up throughout the succeedingde-energized period of the line circuit.

The fifth de-energized period or time space on the line circuit isrepeated by the relay FP, causing the stepping relay IV to bede-energized in a manner later to be explained in detail.

Thus, the application of the sixth impulse to the line circuit and theresulting response of the relay FP causes the relay V]? to again dropaway by reason of the closure of its bucking stick circuit. This buckingstick circuit is closed from (B), through a circuit including frontcontact I9 of relay VP, back contact I I of relay IV, front contacts I2,I3 and I4 of relays 2V, 3V and 4V respectively, front contact III ofrelay 4V, upper winding of relay VP, front contact I5 of relay SA, frontcontact I6 of relay FP, to (CN). The

direction of current flow in this bucking stick circuit is opposite tothe direction of current flow in the lower winding of the relay VP, sothat the magnetic flux in the relay VP is reduced to substantially zerocausing its contacts to drop away. This de-energized condition of therelay VP remains throughout the following de-energized period of theline circuit I.

The sixth de-energized period or time space on the line circuit isrepeated by the relay FP which causes the stepping relay 2V to bedropped away, as will be later explained in detail.

Thus, the application of the seventh impulse to the line circuit, andthe resulting response of the relay FP, causes the relay VP to be againpicked up by reason. of a circuit closed from (13+), through a circuitincluding back contact I2 of relay 2V, front contacts I3 and H of relays3V and 4V respectivly, front contact I of relay 4V, upper winding ofrelay VP, front contact I5 of relay SA, front contact l6 of relay FP, to(ON). This energization of the relay VP causes its contacts to be pickedup thereby closing its stick circuit including its front contact I0, sothat the relay VP remains picked up throughout the succeedingde-energized period of the line circuit.

The seventh de-energized period or time space marked off on the linecircuit is repeated by the relay FP causing the stepping relay 3V to bedropped away in a manner to be later explained in detail.

Thus, the application of the eighth impulse to the line circuit and theresulting response of the relay FP causes the relay VP to be againdropped away by reason of the closure of its bucking stick circuit. Thisbucking stick circuit is closed from (B-), through a circuit includingfront contact ill of relay VP, back contact I3 of relay 3V, frontcontacts I4 and III of relay 4V, upper winding of relay VP, frontcontact I5 of relay SA, front contact ii of relay FP, to (CN). Thedirection of current flow in this bucking stick circuit is opposite tothe direction of current flow in the lower winding of relay VP, so thatthe magnetic flux in its core structure is reduced to substantially zerocausing its contacts to drop away. This deenergized condition of therelay VP remains throughout the following deenergized period of the linecircuit I,

The eighth deenergizedperiod of the line circuit is repeated by therelay VP causing the relay tv to be dropped away in a manner to be laterexplained in detail.

As the series of impulses assumed for the embodiment of the presentinvention is considered to comprise eight impulses and eight timespaces, it is apparent that the completion of the series of impulses hasreturned the half step relay to its normal position, as well as all ofthe full step relays. This last time space or deenergized period ontheline circuit is, of course, prolonged for a definite period(providing another series of impulses is immediateiy following) in whichperiod the relay SA drops away. However, if another series of impulsesis not immediately following, this eighth deenergized period isprolonged indefinitely until such time as the system is again initiatedinto operation.

It should be noted here that if the stepping relay bank included an oddnumber of full step relays V instead of an even number as illustrated,the relay VP would still be picked up at the end of the last impulse,but in such a case the relay VP is restored to normal at the end of thedeenergized period for that series by reason of the opening of frontcontacts I5 and ll of the relay SA which drop at the end of each seriesof impulses.

From the above description, it is apparent that the relay VP is operatedto picked up and dropped away positions alternately upon the picking upof the contacts of the relay FP throughout the cycle of operationcomprising the sequential picking up of the relays 2V, 3V, and 4V andtheir sequential deenergization.

Although the relay VP has been illustrated as being of the differentialtype for this specific embodiment of the present invention, it is to beunderstood that any other type of VP relay may be employed, such as atwo-position polar magnetic stick relay shown in the application ofPreston and Hitchcock, Ser. No, 455,304 filed May 24, 1930,corresponding to Australian Patent 1501 of 1931, or just a neutral stickrelay with proper pick-up and stick circuits to provide the re quiredoperation as shown in the Patent to Brixner, 1,995,272 dated March 19,1935.

Operation of stepping relays.The manner in which stepping relays IV, 2V.3V, and V are caused to be picked up successively and then to ,bedropped away successively will now be explained.

The application of the first impulse to the line circuit results in thepicking up of the relay VP which is stuck up until the application ofthe second impulse. Thus, when the first deenergized period or timespace on the line circuit is repeated by the relay FP, the pick-upcircuit for the stepping relay IV is closed from through a circuitincluding front contact I I of relay SA, back contact of relay FP, frontcontact 2| of relay VP, back contacts 22 and 24 of relays 4V and 2Vrespectively, lower winding of relay IV, to The response of the contactsof the relay IV closes its stick circuit from through a circuitincluding front contact I! of relay SA, front contact 26 of relay IV,lower winding of relay IV, to

With the stepping relay IV picked up during the first deenergized periodof the line circuit I, the application of the second impulse causes therelay VP to drop away, as previously described.

Thus, when the second deenergized period of the line circuit is repeatedby the relay FP, the pick-up circuit for the relay 2V is closed fromthrough a circuit including front contact ll of relay SA, back contact20 of relay FP, back contact 2i of relay VP, back contact 23 of relay3V, front contact of relay IV, lower winding of relay 2V, to Theresponse of the contacts of the relay 2V closes its stick circuit fromthrough a circuit including front contact I! of relay SA, front contact21 of relay 2V, lower winding of relay 2V, to

With the stepping relay 2V picked up during the second deenergizedperiod of the line circuit I, the application of the third impulsecauses the relay VP to be picked up, as previously described.

Thus, when the third deenergized period or time space marked off on theline circuit is repeated-by the relay PT, the pick-up circuit for therelay 3V is closed from through a circuit including front contact I! ofrelay SA, back contact 20 of relay FP, front contact 2| of relay VP,back contact 22 of relay 4V, front contact 24 of relay 2V, lower windingof relay IV, to The response of the contacts of the relay 3V closes itsstick circuit from through a circontact II of relay VP, front contact 35of relay 3V, front contact 31 of relay IV, lower winding of relay 4V, toThe response of the contacts of the relay 4V closes its stick circuitfrom through a circuit including front contact I! of relay SA, frontcontact 23 of relay 4V, lower winding of relay 4V, to

With the stepping relay 4V picked up during the fourth deenergizedperiod marked off on the line circuit, the application of the fifthimpulse causes the relay VP to be picked up, as previously described.

Thus, when the fifth deenergized period or time space marked off on theline circuit is repeated by the relay FP, a differential energizingstick circuit for the relay IV is closed from through a circuitincluding front contact I! of relay SA, back contact 20 of relay FP,front contact 2| of relay VP, front contact 33 of relay 4V, frontcontact 36 of relay 2V, front contact 33 of relay IV, upper winding ofrelay 1V, to

It is readily apparent, that the direction of current flow in thisdifferential stick circuit is opposite to the direction of current flowin the stick circuit of relay IV including its lower winding. Thus, themagnetic fluxes produced by the upper and lower windings buck eachother, so that the resulting magnetic fiux in the core structure of therelay is substantially zero, which allows the contacts of the relay IVto drop away. The simultaneous opening of stick contacts 33 and 26 opensboth of the energizing circuits of the relay IV, so that it remainsdeenergized throughout the remainder of the cycle of operation.

With the stepping relay IV dropped away during the fifth deenergizedperiod and with the remaining stepping relays still picked up, theapplication of the sixth impulse causes the relay VP to drop away, aspreviously described.

Thus, when the sixth deenergized period of the line circuit is repeatedby the relay FP, a differential energizing stick circuit for the relay2V is closed from through a circuit including front contact ll of relaySA, back contact 20 of relay FP, back contact 2| of relay VP, frontcontact 35 of relay 3V, back contact 31 of relay IV, front contact 32 ofrelay 2V, upper winding of relay 2V, to The direction of current flow inthe upper winding of relay 2V is opposite to the direction of currentflow in the lower winding of the relay 2V, so that the resultant flux inthe relay is reduced to substantially zero, and its contacts drop away.This deenergized condition of the relay 2V maintains throughout theremainder of the cycle of operation.

With the stepping relay 2V dropped'away during the sixth deenergizedperiod marked off on the line circuit, the application of the seventhimpulse causes the relay VP to be picked up, as previously described.

Thus, when the seventh deenergized period of the line circuit isrepeated by the relay FP, a differential stick circuit for the relay 3Vis closed from through a circuit including front contact ll of relay SA,back contact-20 of relay FP,

front contact ZI of relay VP, front contact 34 of relay IV, back contact36 of relay 2V, front contact 3I of relay 3V, upper winding of relay 3V,to The direction of current flow in the upper winding of relay 3V isopposite to the direction of current fiow in the lower winding of relay3V, so that the resultant flux in the relay is reduced to substantiallyzero, and its contacts drop away. This deenergized condition of therelay 3V maintains throughout the remainder of the cycle of operation.

With the stepping relay 3V dropped away during the seventh deenergizedperiod of the line circuit, the application of the eighth impulse causesthe relay VP to drop away, as previously described.

Thus, when the eighth deenergized period of the line circuit is repeatedby the relay FP, a

differential stick circuit for the relay 4V is closed.

from through a circuit including front contact ll of relay SA, backcontact 20 of relay FP, back contact 2| of relay VP, back contact 35 ofrelay 3V, front contact 30 of relay 4V, upper winding of relay 4V, toThe direction of current fiow in the upper winding of the relay 4V isopposite to the direction of current flow in the lower winding of relay4V, so that the resultant flux in the relay is reduced to substantiallyzero, and its contacts drop away.

As this eighth deenergized period marks the end of the series ofimpulses, the relay SA drops away after a predetermined time openingfront contact I'l thereby insuring that all of the stepping relays havebeen dropped away. Although only four stepping relays have beenillustrated, it is to be understod that any number of relays may beprovided.

Having thus described the stepping operation, it is convenient to nowpoint out the closure of the channel circuits.

Channel circuits.As explained above, the half step relay VP operatesduring the energized periods of the line circuit; while the full steprelays V assume their new positions during the deenergized periods.Thus, the shift from one channel circuit to another, by the relays V isaccomplished while the channel circuits are not in use.

The channel circuits are indicated as energized with positive ornegative potential in accordance with right or left hand positions ofthe polar contact 3 of line relay F, and as terminating at the referencecharacters having letter characters CH with preceding numeralsdesignating the order in which these channel circuits are made up. Forexample, the first channel circuit is designated by ICI-I and iscompleted during the first energized period following the response ofthe relay SA to close its front contact 46 and prior to the response ofany of the stepping relays, thereby including the back contacts 38, 39,40 and ll of the stepping relays 5V, 3V, 2V, and IV respectively.

During the first deenergized period after the first impulse on the linecircuit, the polar contact 3 assumes a neutral deenergized position andthe relay FP operates to a deenergized position causing the response ofthe stepping relay IV. This prepares the channel circuit 20H by closureof front contact ll of relay IV. Thus, upon the application of thesecond impulse, the second chanupon the position of contact 3 of therelay F, through a circuit including front contact 46 of relay SA, backcontacts ll, 39, and 40 of relays IV, IV, and 2V respectively, frontcontact I of relay IV, windings of relay SR to (ON). The polar contact Iof relay SR is operated to a right or a left hand position dependingupon whether the relay SR is energized with positive or negativepotential respectively.

The channel circuits are thus completed sequentially as the steppingrelays are picked up. Similarlyhupon the sequential deenergization ofthe stepping relays, channel circuits are also completed. For example,upon the application of the seventh impulse following the sixth timespace, during which the stepping relay IV is dropped away as previouslydescribed, the relay DR receives positive or negative potentialdepending upon the character of that impulse as repeated by the polarcontact 3 of line relay F. More specifically, this channel circuit isclosed from (18+) or (B-) with the polar contact 3 of the relay F in aright or a left hand position respectively, through a circuit includingfront contact 6 of relay SA, front contacts 38 and 42 of relay 4V, frontcontact 43 of relay 3V, back contact 44 or relay 2V, windings of relayDR, to (CN). The polar contact 8 of relay DR is actuated to a right or aleft hand position depending upon whether positive or negative potentialis applied to the windings of this relay.

and 4V may be employed for other purposes than for the reception of codeimpulses, as illustrated. It is also to be noted, that the front contact46 of the relay SA is not essential to the usual operation of thedisclosure, but is provided to prevent the momentary energization of achannel circuit due to a surge on the line circuit, which surge wouldusually be of insuflicient duration to allow for the pick-up of a relaySA.

Modified form of Fig. 2.-The relays F, FP, BA, VP, SR, and DR are thesame relays in Fig. 2 as in Fig. 1 and therefore have been given thesame reference characters. The relay FP of Fig. 2 has two extra contacts63 and 64, and the relay VP has an extra contact 62. The stepping relaysV of Fig. 2 operate similar to the stepping relays of Fig. 1 and thushave been given corresponding reference characters with distinctiveexponents. These stepping relays IV, 2V 3V, and 4V have only singlewindings, while the stepping relays of Fig. l are provided with doublewindings.

As the control of the relay VP is the same in Figs. 1 and 2, and as thedescription of the operation for Fig. 1 will read directly upon theassociated circuits, the contacts on the stepping relays IV, 2V 3V, andIV, which control the relay VP have been given the same referencecharacters as in Fig. 1. Similarly, the contacts on the stepping relaysof Fig. 2 which are included in the channel circuits have been given thesame reference characters as in Fig. 1. However, those contacts whichare employed on the stepping relays to control their pick-up and stickcircuits have been given distinctive reference characters, as thecircuit arrangement is somewhat different and as certain of thesecontacts are of the make before-break type.

As previously mentioned, the operation of the half step relay upon thereception of a series of impulses to comprise a cycle of operations isidentical with the operation already described in contive potential from(13+) or (B depending nection with Fig. 1. Also, the channel circuitsare closed in the same way and are identical with the channel circuitsof Fig. 1. Thus, the description of Fig. 2 will be directed moreparticularly to the pick-up and drop-away features of the steppingrelays.

One of the objects of this modification shown in Fig. 2 is to providestepping relays which are controlled positively without differentialcircuits. This is accomplished in accordance with the invention byopening the stick circuits of the stepping relays at the right timesinstead of forcing them down, as disclosed in Fig. 1. This arrangementwill be best understood by considering the operation of the steppingrelays.

The application of the first impulse to the line circuit is repeated bythe relays F, FF, and SA sequentially, as previously described. Thepicking up of the relay FP causes the picking up of the relay VP duringthe first impulse.

Thus, when the first deenergized period after the first impulse on theline circuit is repeated by the relay FP, a pick-up circuit for therelay IV is closed from through a circuit including front contact I! ofrelay SA, back contact 2! of relay FP, front contact II of relay VP,back contacts 50 and 52 of relays IV and 2W respectively, windings ofrelay IV", to The response of the contacts of the relay IV to thisenergization closes a stick circuit completed from through a circuitincluding back contact 58 of relay 4V front contact 51 of relay IV,windings of relay IV, to

With the stepping relay IV picked up during the first deenergized periodof the line circuit, the application of the second impulse causes therelay VP to drop away, as previously described.

Thus, when the second deenergized period of the line circuit is repeatedby the relay FP, a pick-up circuit for the relay 2W is closed fromthrough a circuit including front contact I! of relay SA, back contact20 of relay FP, back contact 2| of relay VP, back contact 5| of relay3V, front contact 53 of relay IV, windings of The response of thecontacts of relay 2V closes a stick circuit from through a circuitincluding front contact 6| of relay IV, front contact 56 of relay 2V",windings of relay 2V, to

With the stepping relay 2V picked up during the second deenergizedperiod marked oil on the line circuit, the application of the thirdimpulse on the line circuit causes the relay VP to be picked up, aspreviously described.

Thus, when the third deenergized period of the line circuit is repeatedby the relay FP, a pick-up circuit for the relay 3V is closed fromthrough a circuit including front contact ll of relay SA, back contact20 of relay FP, front contact 2| of relay VP, back contact 5|! of relay4V front contact 52 of relay 2V, windings of relay 3V, to The responseof the contacts of the relay 3V closes its stick circuit from through acircuit including front contact 80 of relay 2V stick contact 55 of relay3V windings of relay 3V to With the stepping relay 3W picked up duringthe third deenergized period of the line circuit, the application of thefourth impulse causes the relay VP to drop away, as previouslydescribed.

Thus, when the fourth deenergized period of the line circuit is repeatedby the relay FP, a pick-up circuit for the stepping relay P is closedfrom through a circuit including front contact ll of relay SA, backcontact 20 of relay FP, back contact 2| of relay VP, front contact 5| ofrelay 3V, windings of relay 4V, to The response of the contacts of therelay 4V closes its stick circuit from through a circuit including frontcontact 59 of relay 3V front contact 54 of relay 4V windings of relay4V, to

The picking up of the stepping relay 4V during the fourth deenergizedperiod of the line circuit transfers the stick circuit of relay IV fromback point 58 to front point 58. This transfer then completes a stickcircuit for the relay IV", from through a circuit including frontcontact l1 of relay SA, back contact 62 of relay VP, front contact 58 ofrelay 4V and stick contact 51 of relay 1V windingsof relay IV to Thistransfer is accomplished without an interruption as the contact 58 is ofthe make-beforebreak type, as conventionally indicated in the drawings.

With the stepping relay 4V picked up during the fourth deenergizedperiod of the line circuit, the application of the fifth impulse causesthe relay VP to be picked up, as previously described.

The picking up of the contact 62 of relay VP would open the stickcircuit for the relay IV if it were not for the fact that the frontcontact 64 of relay FP was closed prior to the response of the relay VPduring this fifth impulse period. In other words, during the fifthimpulse period, after the response of the relay VP, the relay IV ismaintained energized through a stick circuit closed from through acircuit including front contact l1 of relay SA, front contact 64 ofrelay FP, front contact 58 of relay 4V front contact 51 of relay 1Vwindings of relay IV, to

Thus, when the fifth deenergized period of the line circuit is repeatedby the relay FP, the front contact 64 opens, thereby breaking the stickcircuit of the relay IV This dropping away of the relay IV transfers thestick circuit of relay 2V from front contact 6| to back contact 61 whichmaintains relay 2V energized by a circuit closed from through a circuitincluding front contact H of relay SA, front contact 62 of relay VP,back contact 6| of relay 1V front contact 56 of relay 2V windings ofrelay 2V, to This transfer is completed without an interruption of theenergization of the relay 2V as the contact 61 is of themake-before-breakv type.

With this stepping relay IV dropped away during the fifth deenergizedperiod of the line circuit, the application of the sixth impulse causesthe relay VP to be dropped away, as previously described.

The dropping away of the relay VP opening front contact 62 would openthe stick circuit for the stepping relay 2V if it were not for theclosure of front contact 63 of relay FP during this sixth energizedperiod. There is no interruption in the stick circuit for the relay 2Vas the relay FP closes front contact 63 prior to the opening of frontcontact 62 of relay VP.

Thus, when the sixth deenergized period of the line circuit is repeatedby the relay FP, the front contact 63 of relay FP opens, therebydeenergizing the stepping relay 2V allowing its contacts to drop away.The dropping away of the contacts of the relay 2V transfers the stickcircuit of the stepping relay 3V from front contact 60 to back contact60 which then completes the stick circuit for the relay 3V from througha circuit including front contact l1 of relay SA,

back contact 62 of relay VP, back contact 68 of relay 2V-, front contactof relay 3V windings of relay 3V, to

With the stepping relay 2V dropped away during the sixth deenergizedperiod of the line circuit, the application of the seventh impulsecauses the relay VP to be picked up, as previously described. Theopening of back' contact 62 of relay VP would open the stick circuit forrelay 3V if it were not for the closure of front contact 64 of relay FPprior to, the-response of relay VP to the seventh impulse period.

Thus, when the seventh deenergized period of the line circuit isrepeated by the relay FP, its front contact 64 opens, therebydeenergizing the stick circuit of the relay 3V allowing its contacts todrop away. The dropping away of the contacts of the relay 3V transfersthe stick circuit of the relay 4V from front contact 59 to back contact59, thereby completing a stick circuit for the relay 4V from through acircuit including front contact l1 of relay SA, front contact 62 ofrelay VP, back contact 59 of relay 3V stick contact 54 of relay 4Vwindings of relay 4V, to

With the stepping relay 3V dropped away during the seventh deenergizedperiod of the line circuit, the application of the eighth impulse causesthe relay VP to drop away, as previously described, thus opening thefront contact 62 of relay VP which would open the stick circuit of therelay 4V if it were not for the fact that the front contact 63 of relayFP was closed prior to the response of the relay VP.

Thus, when the eighth deenergized period of the line circuit is repeatedby the relay FP, its front contact 63 opens, thereby deenergizing thestick circuit for the relay 4V allowing its contacts to drop away.

As the eighth deenergized period marks the end of the series of impulsesapplied to the line circuit for one cycle of operations, the relay SAdrops away after a predetermined time. Thus, the stepping relays havebeen returned to their normal positions and all of the channel circuitshave been completed in the same order and in the same manner, asdescribed in connection with Fig. 1.

Modified form of Fig. 3.--With reference to Fig. 3, a modifiedarrangement of the stick circuits of the stepping relays IV 2V 3V, and4V of Fig. 2 has been illustrated. In place of the contacts 63 and 64 ofrelay FP in Fig. 2, new contacts 10, 1|, 12, and 13 are provided.Similarly,

in place of contact 62 of relay VP in Fig. 2, new

contacts 14 and 15 are employed. The make-before-break contacts 58, 59,60, and BI of the stepping relays in Fig. 2 are replaced by the contacts16, 11, 18, and 19 respectively.

The pick-up circuits for the relays 1V 2V 3V and 4V are identical withthe pick-up circuits illustrated in Fig. 2, and thus have not been shownin connection with Fig. 3.

Thus, it will be assumed that each of the stepping relays is suitablypicked up on its respective period in the cycle of operation, and thestick circuits completed for each of these relays, when thus picked up,will now be pointed out.

When relay IV is picked up on the first deenergized period or time spacein the series of impulses of the line circuit, a stick circuit is closedfrom through a circuit including front contact l1 of relay SA, backcontact 16 of relay 4V stick contact 51 of relay 1V windings of relayIV, to

When relay 2V is picked up on the second deenergized period of the linecircuit, a stick circuit is closed from through a circuit includingfront contact I! of relay SA, front contact 19 of relay IV, stickcontact 56 of relay 2V", windings of relay 2V, to

When relay 3V is picked up on the third deenergized period of the linecircuit, a stick circuit is closed from through a circuit includingfront contact I I of relay SA, front contact ll of relay 2V", stickcontact of relay 3V, windings of relay IV, to

When relay 4V is picked up on the fourth deenergizedperiod of the linecircuit, a stick circuit is closed from through a circuit includingfront contact ll of relay SA. front contact 11 of relay 3V, stickcontact M of relay 4V, windings of relay IV, to

With all of the stepping relayspicked up and stuck up, as aboveconsidered, the response of the relay 4V would open the stick circuit ofthe relay IV were it not for the closed condition of another branch ofthe stick circuit by reason of the position of the relay VP, which isnow down. This stick circuit for the relay IV during the fourthdeenergized period of the line circuit is closed from through a circuitincluding front contact ll of relay SA, back contact 15 of relay VP,front contact 51 of relay IV, windings of relay lV'*,to

Then upon the application of the fifth impulse which is repeated by therelay FP, another stick circuit including the front contact 13 of relayFF is closed for the relay IV, and the relay VP is picked up during thisperiod opening back contact 15. Thus, upon the fifth deenergized periodof the line circuit, relay FF is deenergized opening front contact I3,thus allowing relay IV to drop away.

The drop-away of the relay IW opens its front contact 19 thereby makingthe relay 2W dependent on the front contact 15 of relay VP which is nowclosed, so that the relay 2V is maintained energized during the fifthdeenergized period. During the sixth impulse period, the relay VP isdropped away opening front contact 15, but, before this occurs, thefront contact 12 of relay F? is closed, so that the relay 2V ismaintained energized until the sixth deenergized period or time space atwhich time the front contact 12 of relay FP opens.

The drop-away of relay 2V opens its front contact II, which woulddeenergize relay 3V but the back contact H of relay VP is closed duringthe sixth deenergized period maintaining the relay 2V stuck up; Thenupon the seventh impulse period the back contact 14 is opened a shorttime after the front contact if of relay FF is closed, so that relay3V'-' is maintained stuck up until the seventh deenergized period atwhich time it is dropped away upon the opening of front contact 1 ILikewise, the drop-away of the relay 3V opens its front contact II whichwould allow the relay 4V to drop away if it were not for the closedcondition of front contact H of relay VP during the seventh deenergizedperiod. Then upon the eighthimpulse period just before the relay VPdrops away, the front contact 10 of relay FF is closed, therebymaintaining relay 4V energized until the opening of front contact 10upon the reception of the eighth deenergized period by the relay PP.

The front contact ll of relay SA controls the stick circuit of the relayVP, as already explained in connection with Figs. 1 and 2.

From the above description it is readily apparent that themake-before-break contacts on the stepping relays have been eliminatedby providing contacts on the relays PP and VP in such relationship thatthe stick circuits for the stepping relays are maintained closed duringtransition periods until it is proper for the stepping relays to bedropped out.

Thus, a stepping relay bank has been shown and described which employseach stepping relay to close two channel circuits by reason of thesequential picking up of the stepping relays in the series which are allheld up until the sequential dropping away of these relays in the sameorder that they were picked up. This provides the increased number ofchannel circuits by a type of repeat, which requires no additionalrelays as has been the case in certain prior systems.

Having thus described a stepping relay bank for use in selector typecommunication systems, as embodiments of the present invention, it isdesired to be understood that the forms were selected to facilitate thedisclosure of the invention rather than to limit the number of formswhich it may assume; and, it is to be further understood that variousmodiflcations, adaptations and alterations may be applied to thespecific forms shown to meet the requirements of practice, without inany manner departing from the spirit or scope of the present inventionexcept as limited by the appended claims.

What I claim is:-

1. In combination; a line relay for repeating a series of time spacedimpulses; a series of stepping relays; means for sequentially picking upsaid stepping relays, one for each time space repeated by said linerelay until all of said stepping relays are picked up; means forsticking up said stepping relays, the first stepping relay of saidseries being stuck up by a circuit including a back contact of the laststepping relay of said series, and the remaining stepping relays of saidseries being stuck up by a circuit including a front contact of itsimmediately preceding stepping relay of the series; means effective uponthe picking up of the last stepping relay of the series to maintain saidfirst stepping relay of the series stuck up only until the next timespace in said series of impulses occurs; means effective upon thedropping away of each stepping relay during its respective time space tomaintain the next succeeding stepping relay stuck up only until the nextsucceeding time space occurs in said series of impulses; and meansincluding said stepping relays for closing a plurality of channelcircuits, one upon the picking up of each stepping relay and one uponthe dropping of each stepping relay.

2. In combination; a line relay for repeating a series of time spacedimpulses; a series of stepping relays; means for sequentially picking upsaid stepping relays, one for each time space repeated by said linerelay until all of said stepping relays are picked up; means forsticking up said stepping relays, the first stepping relay of saidseries being stuck up by a circuit including a back contact of the laststepping relay of said series, and the remaining stepping relays of saidseries being stuck up by a circuit including a front contact of itsimmediately preceding stepping relay of the series, means effective uponthe picking up of the last stepping relay of the series to maintain saidfirst stepping relay of the series stuck up only until the next timespace in said series of impulses occurs; means effective upon thedropping away of each stepping relay during its respective time space tomaintain the next succeeding stepping relay stuck up only until the nextsucceeding time space occurs in said series of impulses; and meansincluding said stepping relays for closing a plurality of channelcircuits, one upon each picking up or upon each dropping of saidstepping relays during the following impulse in said series of impulses.

3. In combination; a line relay for repeating a series of time spacedimpulses; a series of stepping relays; means for sequentially picking upsaid stepping relays, one for each time space repeated by said linerelay until all of said stepping relays are picked up; means forsticking up said stepping relays, the first stepping relay of saidseries being stuck up by a circuit including a back contact of the laststepping relay of said series, and the remaining stepping relays of saidseries being stuck up by a circuit including a front contact of itsimmediately preceding stepping relay of the series; means efiective toshunt said back contact of the last stepping relay of said series priorto its picking up, whereby said first stepping relay is maintained stuckup, said means being effective only until the next time space in saidseries of impulses occurs, means effective to shunt said front contactof each stepping relay prior to its dropping away during its respectivetime space of said series of impulses, whereby the next succeedingstepping relay is maintained stuck up, said means being effective onlyuntil the next succeeding time space in said series of impulses occurs;and means including said stepping relays for closing a plurality ofchannel circuits, one upon the picking up of each stepping relay and oneupon the dropping of each stepping relay.

4. In combination; a line relay for repeating a series of time spacedimpulses; a series of stepping relays; means for sequentially picking upsaid stepping relays, one for each time space repeated by said linerelay until all of said stepping relays are picked up; means forsticking up said stepping relays, the first stepping relay of saidseries being stuck up by a circuit including a back contact of the laststepping relay of said series, and the remaining stepping relays of saidseries being stuck up by a circuit including a front contact of itsimmediately preceding stepping relay of the series; means eifective uponthe picking up of the last stepping relay of the series to transfer thestick circuit of said first stepping relay through a front contact ofsaid last relay to render said stick circuit of said first relaydeenergized upon the occurrence of the next time space in said series ofimpulses; means efiective upon the dropping away of each stepping relayduring its respective time space to transfer the stick circuit of thenext succeeding stepping relay through a back contact of said particularstepping relay to render said stick circuit of said next succeedingstepping relay deenergized upon the occurrence of the next succeedingtime space in said series of impulses; and means including said steppingrelays for closing a plurality of channel circuits, one upon the pickingup of each stepping relay and one upon the dropping of each steppingrelay.

5. In combination, a series of stepping relays, a contact closedintermittently, a pick-up circuit for each of said stepping relays, saidpick-up circuits being in part controlled by said stepping relays and inpart by said contact and closed sequentially until all of said steppingrelays have been energized, a preliminary holding circuit for eachstepping relay controlled by said stepping relays and closed until afinal holding circuit for such relay is closed, a final holding circuitfor each of said stepping relays controlled by a contact operatingsynchronously with said first mentioned contact but opened when saidfirst mentioned contact is closed, means for opening said final holdingcircuits for said stepping relays in the same order that theirrespective pick-up circuits are closed, and means controlled by saidpreliminary and said final holding circuits for causing the sequentialoperation of said stepping relays in response to the intermittentclosure of said contact.

6. In combination, a series of stepping relays, a contact closedintermittently, a pick-up circuit for each of said stepping relays, saidpick-up circuits being in part controlled by said stepping relays andclosed sequentially until all of said stepping relays have beenenergized, a preliminary holding circuit for each stepping relaycontrolled by said stepping relays, a final holding circuit for eachstepping relay, means including a contact opened when said firstmentioned contact is closed for controlling said final holding circuit,an intermediate holding circuit for each stepping relay, means includingsaid intermediate holding circuit for holding such relay energizedduring the time between the opening of the preliminary and the closingof the final holding circuit for such relay, and means controlled bysaid preliminary, said final and said intermediate holding circuits forcausing the sequential operation of said stepping relays in response tothe intermittent closure of said contact.

7. In a registering system, an impulse relay operated by a series ofimpulses, a series of stepping relays, a steering relay, an energizingcircuit for said stepping relays including a contact of said steeringrelay, means responsive to a first operation of said impulse relay forcompleting said energizing circuit through said contact in one positionwhereby one of said stepping relays is operated, means responsive to asecond operation of said impulse relay for completing said energizingcircuit through said contact in another position whereby another of saidstepping relays is operated, means responsive to said first and secondoperations of said impulse relay for alternately operating and releasingsaid steering relay, whereby its contact is alternately shifted from oneposition to another, and means responsive to further operations of saidimpulse relay and the operation and release of said steering relay forsequentially releasing said stepping relays in the same sequence inwhich they are operated.

8. In combination; a line relay intermittently operated in response to aseries of impulses comprising a code; a series of stepping relays whichassume operated or released positions depending upon whether or nottheir windings are energized; a steering relay common to said steppingrelays; means controlled by the impulses repeated by said impulse relayfor operating said steering relay; pick-up circuits for sequentiallyoperating said stepping relays in a certain order, one for each of afirst part of the impulses repeated by said line relay; stick circuitsfor holding said stepping relays operated; releasing circuits includinga difierential winding on each relay for effecting the sequentialrelease of said relays, one for each of a second part of the imtrolledby said steering relay for steering the first and second parts of saidimpulses to said stepping relays.

9. In combination; a line relay intermittently operated in response to aseries of impulses comprising a code; a series of stepping relays whichassume operated or released positions depending upon whether or nottheir windings are energized; a steering relay common to said steppingrelays; means controlled by the impulses repeated by said impulse relayfor operating said steering relay; pick-up circuits for sequentiallyoperating said stepping relays in a certain order, one for each impulserepeated by said line relay; stick circuits for holding said steppingrelays operated; releasing circuits including a differential winding oneach relay for effecting sequential release of said relays in the sameorder as they were operated, one for each impulse repeated by said linerelay; and means controlled by said steering relay for steering saidimpulses to said stepping relays.

10. In combination; a line relay intermittently operated in response toa series of impulses comprising a code; a series of stepping relayswhich assume operated or released positions depending upon whether ornot their windings are energized; a single half-step relay; means foroperating said halt-step relay in response to said impulses; pickupcircuits for sequentially operating said stepping relays in a certainorder, one for each impulse repeated by said line relay; stick circuitsfor holding said stepping relays operated; means for sequentiallybreaking said stick circuits; means responsive to breaking the stickcircuits oi said stepping relays tor releasing said stepping relays inthe same order as they were operated, one for each impulse impressed onsaid line circuit; and means controlled by said half-step relay forsteering said impulses to said stepping relays for controlling theiroperation and release.

11. In combination; an intermittently operating contact; a series ofstepping relays which assume operated or released positions dependingupon whether or not their windings are energized; a single half-steprelay; means controlled by the operation of said contact for operatingsaid halfstep relay; operating circuits for sequentially operating saidstepping relays in a certain order, one for each closure of saidcontact; means including said contact for selectively energizing saidcircuits; stick circuits for holding said stepping relays operated;means for energizing said stickcircuits; means for sequentially breakingsaid stick circuits; means responsive to the sequential breaking of saidstick circuits for efi'ecting sequential release of said relays; andmeans controlled by said half-step relay for steering the impulsesproduced by said intermittently operating contact to the circuits ofsaid stepping relays for controlling their operation and release.

12. In combination; an intermittently operating contact; a series ofstepping relays which assume operated or released positions dependingupcn whether or not their windings are energized; a single halt-steprelay operated in response to the operation of said contact; circuitsfor sequentially operating said stepping relays in a certain order, onefor each closure of said contact; stick circuits for holding saidstepping relays operated; means for sequentially breaking said stickcircuits; means responsive to thebreaking of said stick circuits forefiecting sequential release of said relays in the same order as theywere operated, one for each closure of said contact; and meanscontrolled by said half-step relay for steering the impulses produced bysaid intermittently operating contact to said stepping relays forcontrolling their operation and release.

13. In combination; a contact; a series of stepping relays which assumeoperated or released positions depending upon whether or not theirwindings are energized; a single half-step relay operated in response tothe operation of said contact; circuits for sequentially operating saidstepping relays in a certain order, one for each closure of saidcontact; stick circuits each including the winding of only a singlerelay for holding saidstepping relays operated; means for breaking thestick circuits for said stepping relays in the same order as said relayswere energized, one for each closure of said contact; and meanscontrolled by said half-step relay for steering the impulses produced bysaid intermittently operating contact to said stepping relays forcontrolling their operation and release.

14. In combination, a plurality of stepping relays, a half-step relayhaving contacts capable of being shifted from one position to another,means for applying a series of impulses to the circuits of said steppingand half-step relays, means controlled by the contacts of said halfsteprelay in each position for steering certain ones of said impulses tocertain circuits of said stepping relays whereby said stepping relaysare sequentially operated in response to said series of impulses, meansfor sticking the operated stepping relays, means controlled by thecontacts of said half-step relay in each position for steering certainothers of said impulses to certain other circuits of said steppingrelays whereby said stepping relays are sequentially released, and meanscontrolled by each impulse of said series for shifting the contacts ofsaid half-step relay from one position to another.

15. In combination, a plurality of stepping relays, a half-step relayhaving contacts capable of being shifted from one position to another,means for applying a series of impulses to the circuits of said steppingand half-step relays, means controlled by the contacts of said halfsteprelay in each position for steering certain ones of said impulses tocertain circuits 01' said stepping relays whereby said stepping relaysare sequentially operated in response to a first portion 01' said seriesof impulses, means for sticking the operated stepping relays, meanscontrolled by the contacts of said half-step relay in each position forsteering certain others of said impulses to certain other circuits ofsaid stepping relays whereby said stepping relays are sequentiallyreleased in response to a second portion of said series of impulses, andmeans controlled by each impulse of said series for shitting thecontacts of said half-step relay from one position to another.

16. In combination; a plurality of stepping relays; a halt-step relaycommon to said stepping relays; circuits for said stepping relays andsaid half-step relay; means for selectively applying a series ofimpulses to said circuits; means responsive to the selective applicationof said impulses to said circuits for operating and releasing saidhalf-step relay; operating means responsive to the selective applicationof certain ones of said impulses to said circuits for sequentiallyoperating said stepping relays; means for sticking the operated steppingrelays; and releasing means responsive to the selective application oicertain others of said impulses to said circuits for sequentiallyreleasing the operated stepping relays, said releasing means includingdiflerential circuits of said stepping relays selected by said half-steprelay in its operated and released positions.

17. In combination; a plurality of double wound relays; circuits forsaid relays; means for selecting and applying a series of impulses tosaid circuits; operating means responsive to the application of certainones of said impulses to said circuits for successively operating saidrelays, said operating means including a pick-up winding of each relay;means for sticking each operated relay over a circuit including itspick-up winding; and

releasing means responsive to the application of certain others of saidimpulses to said circuits for releasing each operated relay, saidreleasing means comprising a circuit selected by a first one of saidrelays which is operated before the operation of a second one oi saidrelays and by a third one of said relays which is operated aftertheoperation of said second relay and including a differential winding onsaid second relay.

18. In combination; an impulse relay intermittently operated to producea series of impulses; a plurality of stepping relays which assumeoperated or released positions depending upon whether or not theirwindings are energized; means including said impulse relay for operatingsaid stepping relays in sequence, one for each impulse produced by saidimpulse relay; means including stick circuits for holding said steppingrelays operated; a single steering relay; means including said impulserelay for operating and releasing said steering relay; steering meanscontrolled by said steering relay for selectively steering said impulsesto said stepping relays; and means controlled by said impulses andincluding said steering means for sequentially releasing said steppingrelays.

OSCAR H. DICKE.

